NWS Twin Cities issues "worm warning"
MINNEAPOLIS -- The forecast for Thursday: wiggly, crawly and slimy.
The National Weather Service Twin Cities issued a tongue-in-cheek "worm warning" for areas south of Interstate 94. The NWS said residents "can expect to see, smell, and step on many worms this morning. Proceed with caution."
The call for caution caused by creepy crawlies comes after the region saw multiple inches of rain fall during a slow-moving storm Thursday morning.
According to the University of Wisconsin, the reason worms emerge from the ground when it rains has to do with their breathing. Worms breathe through their skin, and typically, they can get enough oxygen from the mixture of air and water in soil. When it rains, however, their burrows fill with water. Oxygen diffuses much slower through water, and so worms move to the surface to breathe.
Minnesota has at least 15 species of earthworm, all of which are invasive, according to the state's Department of Natural Resources.
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"We have no evidence that earthworms ever inhabited Minnesota before European settlement," the DNR says. "Even if they did, the glaciers killed any native North American earthworms in our region."
Worms likely first came to Minnesota in the soil brought over on European ships traveling to North America. Their use as fishing bait helped them spread across the state, the DNR said.
While the NWS' warning was a joke, the DNR says earthworms can actually be harmful to Minnesota's ecosystems.
"In areas heavily infested by earthworms, soil erosion and leaching of nutrients may reduce the productivity of forests and ultimately degrade fish habitat," the DNR said.
